Rotor arrangement with balancing element and method for mounting a balancing element

ABSTRACT

A rotor arrangement, with a rotor for an engine having a rotor disc that extends along a circumferential direction about a central axis, and at least one balancing element that is attached at the rotor disc for balancing the rotor. At least one attachment section projecting axially with respect to the central axis is embodied at the rotor disc, and the at least one balancing element engages around the axially projecting attachment section.

REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application No. 10 2017 207 283.0 filed on Apr. 28, 2017, the entirety of which is incorporated by reference herein.

BACKGROUND

The invention relates to a rotor arrangement as well as to a method for mounting a balancing element at a rotor.

The balancing of a rotor for an engine, in particular of a rotor for a gas turbine engine, is usually realized by attaching balancing elements at different balancing positions. Here, the attachment of individual balancing elements is the method of choice, for instance when a selective arrangement of rotor blades at a rotor disc of the motor is not possible and the rotor is made in one piece with the rotor blades as a blisk, for example. While in a rotor in which the rotor blades are manufactured separately and are mounted at the rotor disc a displacement of the rotor blades across the circumference of the rotor can be achieved in a computer-aided manner based on measurements at the individual rotor blades by means of which unbalanced masses are prevented, in a blisk with rotor blades that are embodied in one piece with the rotor disc, there is only the possibility of locally removing material or locally attaching balancing elements in order to compensate for unbalanced masses. At that, with a view to costs and effort, the attachment of balancing elements is usually favored.

What is known from the state of the art in this context are differently designed balancing elements and attachment sections adjusted to them at the rotors of an engine that make it possible to attach the respective balancing elements at the rotor. For instance, it is known from DE 10 2008 016 329 A1 to provide radially inwards facing webs with receiving grooves for respectively one balancing element at a rotor disc extending along a circumferential direction about a central axis of the rotor (with respect to this central axis). Here, the design of the attachment sections for the balancing elements that are defined by the radially inwards facing webs and receiving grooves is comparatively complex. Further, in the rotor arrangement of DE 10 2008 016 329 A1, the balancing elements can only be mounted from the inside and either cannot be removed at all or cannot be removed easily after mounting. Thus, the balancing elements of DE 10 2008 016 329 A1 are to be deformed after attachment for fixating at the respective attachment section, and the attachment sections are not accessible from a radially outer side.

SUMMARY

The invention is thus based on the objective to improve a rotor arrangement with a rotor and at least one balancing element attached thereat and an associated mounting method in particular with respect to the mountability and the balancing of the rotor.

This objective is achieved through a rotor arrangement with features as described herein as well as through a mounting method with features as described herein.

Here, the proposed rotor arrangement has at least one rotor for an engine comprising a rotor disc that extends along a circumferential direction about a central axis of the rotor. Further, at least one balancing element is provided that is attached at the rotor disc for balancing the rotor. Here, the at least one balancing element is attached at least at one attachment section of the rotor disc that protrudes axially with respect to the central axis by the balancing element engaging around the axially projecting attachment section.

Through the at least one axially projecting attachment section in combination with a balancing element that engages around this attachment section, it is not only possible to fixate the balancing element at the rotor disc in a comparatively simple and captive manner in order to balance the rotor. But the balancing element can also remain easily accessible from a radially outer side, for example to be able to alter the position of the at least one balancing element at the rotor disc also after mounting of the rotor in an engine or at least after the assembly of a rotor assembly group comprising the rotor.

For the wrap-around engagement of the attachment section, the at least one balancing element can have a balancing element body with a wrap-around section. By means of this wrap-around section, the balancing element then engages around the axially projecting attachment section.

In an alternative embodiment variant, the wrap-around engagement is realized by means of at least one section of a balancing element body of the balancing element and at least one section of a fixation element that is adjustably mounted at the balancing element body. Here, the fixation element can for example be radially adjustable with respect to the central axis in order to apply a clamping force for fixating the balancing element at the attachment section if the balancing element is present at a desired/predefined balancing position.

At that, it can in particular be provided that the fixation element does not extend through the attachment section. In an exemplary embodiment based hereon, the balancing element engages around the attachment section by the attachment section being clamped between a (with respect to the central axis) radially outwardly positioned section of the balancing element body and a radially inwardly positioned section of the fixation element. The radially inwardly positioned section of the fixation element can for example be a clamping head. This clamping head can then be displaced in the direction of the radially outwardly positioned section of the balancing element body to bring the clamping head in abutment with the attachment section and to fixate the balancing element at the attachment section in a clamping manner.

In one embodiment variant, a wrap-around section of the balancing element body has at least one—with respect to the central axis—radially outer first leg section and at least one radially inner second leg section, wherein then at least one part of the axially projecting attachment section is received between the first and the second leg sections. Thus, at least one part of the axially projecting attachment section that is formed by the rotor disc is received in a sandwiched manner between the first and the second leg sections of the wrap-around section to hold the balancing element at the rotor disc in a form-fitting manner. On the one hand, such a wrap-around engagement of the at least one attachment section of the rotor disc can ensure that the balancing element can be easily attached at the rotor disc in a captive manner, and on the other hand it makes it possible for the already attached balancing element to remain adjustable relative to the rotor disc along the circumferential direction until a fixation of the balancing element at a predefined balancing position occurs.

For a defined abutment of the balancing element body at the at least one attachment section of the rotor disc as well as for an additional axial securing of the balancing element once it is attached at the attachment section, at least one of the first and second leg sections can have a curvature that is convex in the direction of the attachment section. By means of this convex curvature, the balancing element that is mounted at least at one attachment section of the rotor disc according to the intended use can also engage around the attachment section in the axial direction in a possible further development to avoid unintended detachment of the balancing element that is mounted according to the intended use at the rotor disc.

In an embodiment variant with a wrap-around section, the at least one balancing element can also comprise a fixation element that is adjustable relative to the balancing element body. Here, the fixation element may also be radially adjustable with respect to the central axis, for example. At that, the fixation element serves for fixating the balancing element at the axially projecting attachment section after the balancing element body has been arranged thereat.

In this context, the fixation element for fixating the balancing element at the attachment section can for example be configured and adjustably mounted relative to the balancing element body in such a manner that a radial distance of the first and second leg sections can be changed by adjusting the fixation element. Thus, in this variant, it is achieved by means of the fixation element that the first and second facing leg sections can be clamped against each other to enclose the enclosed part of the axially projecting attachment section in between them in a form-fitting and clamping manner, and in this way fixate the balancing element at the rotor disc in a predefined balancing position.

In this variant, the fixation element extends at the rotor arrangement with one section between the first and the second leg sections radially with respect to the central axis, for example to be respectively directly connected to the first and the second leg sections and be able to act on them directly.

In one embodiment variant, the section of the fixation element extending between the first and the second leg sections extends not through the attachment section, but instead past it. The section of the fixation element extending between the first and the second leg sections thus in particular extends not through a bore in the attachment section, but rather axially offset with respect to the attachment section.

In an alternative embodiment variant, the fixation element for fixating the balancing element at the attachment section is configured and adjustably mounted relative to the balancing element body in such a manner that the fixation element can be brought into contact with the attachment section. If, in the previously explained variant, an abutment of the first and the second facing leg sections is achieved on different sides of the axially projecting attachment section through the fixation element, and the balancing element is thus fixated at the attachment section, variant the fixation element itself serves as a counter bearing and with one section is brought into abutment with the attachment section in this alternative embodiment. At that, the fixation element that is supported at the first radially outer (external) side of the attachment section can for example be adjusted, so that the balancing element body is displaced radially outwards and in this way the second radially inner leg section of the wrap-around section is displaced in the direction of a second (internal) side of the attachment section that is located opposite the first (external) side of the attachment section for the fixation element. Consequently, in this variant an area of the attachment section is clamped not between the first and second leg sections engaged around the attachment section, but rather between the fixation element and only one of the first and second leg sections.

For applying a clamping force for fixating the balancing element body in a predefined balancing position, the fixation element can principally form a contact surface via which the fixation element acts—depending on the embodiment variant—on one of the first and second leg sections or the axially projecting attachment section to fixate the balancing element at the attachment section. This contact surface is for example embodied at a (clamping) head of the fixation element. This clamping head then engages behind one leg section, for example the second radially inner leg section, or the attachment section, and/or is pressed against the axially projecting attachment section due to the displacement of the fixation element relative to the balancing element body.

In one embodiment variant, the balancing element and the fixation element respectively have a thread for adjustably fixating the fixation element at the balancing element body. For instance, the fixation element comprises an external thread and the balancing element body comprises an internal thread. Correspondingly, the fixation element can be screwed in with its external thread into an opening or bore of the balancing element body that is provided with the internal thread. If then the fixation element is screwed in further, with the balancing element body being already attached at the axially projecting attachment section (and at that is displaced for example in the radial direction with respect to the central axis), this causes (a) a distance of the first and second leg sections of the wrap-around section or (b) a distance between the fixation element and an opposing (second) leg section to be reduced, so that the balancing element is finally fixated.

In one embodiment variant, the fixation element forms—with respect to the central axis—a radially externally positioned tool interface at which a mounting tool can be applied to adjust the fixation element relative to the balancing element body. At that, the tool interface can for example comprise an external or internal hexagon. The fixation of the balancing element in a desired balancing position can be realized comparatively easily through the arrangement of the tool interface at a radially outwardly positioned side of the balancing element. Likewise, a fixation of the balancing element can be released again in a comparatively easy manner. If the fixation is released, the balancing element body can also be displaced into a different balancing position in the circumferential direction about the central axis via the wrap-around engagement at the axially projecting attachment section. Here, the balancing element and a mounting tool for fixating the balancing element can be embodied in such a manner that, with the fixation released, a displacement of the balancing element body in the circumferential direction is also possible by means of the mounting tool, before the balancing element is then fixated again in a new balancing position by adjusting the fixation element by means of the mounting tool.

In an exemplary embodiment, the wrap-around section of the balancing element body has a trapezoidal contour, as viewed in a side view along the central axis. Here, the longer side of this trapezoidal contour is located radially inside at the rotor arrangement. In this manner, an improved stress development inside the wrap-around section is achieved, in particular if the balancing element is fixated by a fixation element that acts on the attachment section radially outside and at least one radially inner leg section that is displaced by adjustment of the fixation element in the radially outward direction against the attachment section. In particular, disadvantageous bending moments can be reduced in this manner during the fixation of the balancing element.

In an exemplary embodiment, the wrap-around section has two second radially inner leg sections that are positioned opposite a (single) first radially outer leg section. The wrap-around section thus has two separated radially inner leg sections to abut at the axially projecting attachment section at two positions that are spatially offset with respect to one another (in different attachment areas of the attachment sections) via these second leg sections if the balancing element is fixated according to the intended use.

For instance, a recess extending in the circumferential direction is embodied at the wrap-around section between the two second radially inner leg sections. Through this recess, the two second leg sections are spatially separated from each other to achieve a defined force introduction at the leg sections during fixation of the balancing element. In addition, as a result of the material savings associated with the recess, it can be avoided that a weight of the balancing element is significantly increased by the two leg sections as compared to a variant with only one second radially inner leg section.

In one embodiment variant, the attachment section at the rotor disc at which one balancing element or multiple balancing elements can be fixated is embodied in a ring-shaped or ring segment-shaped manner. Here, the ring-shaped or ring segment-shaped attachment section extends along a circle line about the central axis at the rotor disc. During mounting of the balancing element, the balancing element body can be attached at the ring-shaped or ring segment-shaped attachment section, so that the balancing element engages around a part of the attachment section, e.g. by means of the wrap-around section of the balancing element body or by means of the balancing element body and a fixation element. Then, the balancing element body that is held in such a manner at the attachment section can be displaced along the circumferential direction at the ring-shaped or ring segment-shaped attachment section until the balancing element body is in a predefined (other) balancing position, in which an imbalance of the rotor is compensated. Subsequently, the balancing element is fixated at the occupied balancing position, for example by screwing in a fixation element.

Alternatively or additionally, the attachment section has at least two axially projecting attachment areas that are arranged at a distance to one another in the circumferential direction. The respectively axially projecting attachment areas, which may for example be separated from each other by a gap in the circumferential direction, can define different balancing positions for respectively one balancing element, and/or a defined contact point for a fixation element or one of the first and second leg sections of the wrap-around section.

For instance, it is provided in a further development that the attachment section has two outer, respectively axially projecting (first) attachment areas as well as an also axially projecting inner or middle (second) attachment area between the two outer attachment areas. If a balancing element with a radially outer leg section and two radially inner leg sections is used in such an embodiment variant, a balancing position for a possibly to be attached balancing element can be predefined comparatively precisely through the different attachment areas of an attachment sections. In this way, respectively one outer axially projecting attachment area is received between the radially outer first leg section and one of the two radially inner second leg sections, while the inner attachment area serves only for supporting the first leg section or the fixation element. In the latter case, the fixation element itself thus acts on the (second) inner attachment area located between the two outer attachment areas of the attachment section to fixate the balancing element at the attachment section.

To save material and thus weight, a gap can be respectively embodied at the rotor disc between the axially projecting outer attachment areas and the axially projecting inner attachment area.

In principle, multiple preferably geometrically identically embodied attachment sections and/or multiple balancing elements can be provided at the rotor disc. When defined balancing positions along the circumference are prescribed, at which a balancing element according to the intended use can be fixated, the number of these possible balancing positions may be limited. For instance, at least 8, but no more than 24, e.g. 16 to 18, balancing positions at the rotor disc of the rotor may be predefined, at which a balancing element can be fixated according to the intended use.

In particular against this background, multiple attachment sections succeeding each other along the circumferential direction and respectively projecting axially are provided at the rotor disc in one embodiment variant, with respectively one intermediate area having an axial extension that is reduced as compared to the attachment sections being provided in between them. Consequently, here the attachment of a balancing element by axial wrap-around engagement is not possible in the intermediate areas. The possible attachment points for a balancing element at the rotor disc are correspondingly limited. But on the other hand, as a result of the intermediate areas with reduced axial extension, weight is saved in particular with respect to a variant in which an attachment section extends at the rotor disc in a ring-shaped manner. Preferably, an attachment section is respectively embodied in one piece at the rotor disc, thus being formed at the same.

A rotor of the rotor arrangement is for example provided for a gas turbine engine. For instance, it may be a rotor for a compressor stage of the gas turbine engine that is provided with rotor blades, for example a rotor of a high-pressure compressor of the gas turbine engine.

A further aspect of the proposed solution is an improved method for mounting a balancing element at a rotor that is rotatable about a central axis.

Also here, the rotor comprises a rotor disc with at least one attachment section that is axially projecting with respect to the central axis and at which a balancing element for balancing the rotor can be attached. The proposed method comprises at least the following steps:

providing a balancing element with mounting jaws, and

attaching the balancing element to the balancing element body at the at least one attachment section, so that a balancing element engages around the attachment section and at least a part of the attachment sections is received inside the mounting jaws.

Here, the mounting jaws can be defined by at least two facing leg sections of a wrap-around section of the balancing element body of the balancing element, as has already been explained above. Alternatively, the mounting jaws provided for the wrap-around engagement of the attachment section are defined by a section of the balancing element body and a section of a fixation element adjustable thereat, i.e. for example by a leg section of the balancing element body and a clamping head of the fixation element that is positioned opposite this leg section.

Here, the balancing element attached at the attachment section can be displaced along a circumferential direction about the central axis into a balancing position (optionally of multiple possible and predefined balancing positions) and subsequently fixated. As has already been explained above, the balancing element is thus initially attached at the attachment section by means of the balancing element body, and namely in such a manner that the balancing element is held at the rotor disc so as to be still displaceable, in particular shiftable. The balancing element can thus be displaced along the circumferential direction about the central axis of the rotor along an adjustment path predefined by the attachment section, wherein it is ensured that the balancing element body remains at the attachment section by means of the form-fitting wrap-around engagement of the attachment section. If the balancing element body and thus the balancing element take the desired balancing position along the circumference, the balancing element is fixated.

For fixating the balancing element, the fixation element adjustably mounted at the balancing element body may for example be adjusted.

As a part of an embodiment variant of a possible mounting method, a mounting tool is used for attaching the balancing element body at the attachment section, with the balancing element body being held at the mounting tool in a form-fitting manner and being further displaced into the balancing position at the rotor disc by means of the mounting tool. The mounting tool is thus provided for a form-fitting connection to the balancing element body to be able to attach the balancing element body at the rotor by means of the mounting tool in a simple and quick way, namely in such a manner that the wrap-around section of the balancing element body or the balancing element body and the fixation element engage(s) around the attachment section. A displacement of the balancing element body along the circumferential direction is then still facilitated through the mounting tool, so that the balancing element body can be displaced, in particular shifted, into the desired balancing position. The form fit of the balancing element body and the mounting tool is for example provided by a hook-shaped section of the mounting tool. In one embodiment variant, the mounting tool has a section that is embodied as a holding hook and that can be inserted at a corresponding interface of the balancing element body. In a further development, the balancing element body for example has a middle part that is offset with respect to adjoining sections of the balancing element body, and at which a thickness of the balancing element body is reduced and the holding hook of the mounting tool is plugged on to engage around the balancing element body and place it at the rotor by means of the mounting tool.

The mounting tool may for example be embodied with at least two parts, comprising a holding part that holds the balancing element body in a form-fitting manner and a part for displacing of a fixation element that is adjustably mounted at the holding part. Thus, the balancing element body can be attached at the rotor disc by means of the mounting tool, so that e.g. the wrap-around section of the balancing element body engages around the at least one attachment section. Subsequently, the fixation element of the balancing element is adjusted relative to the balancing element body and in this way finally fixated in the desired balancing position my means of the balancing element by using the same mounting tool—and without having to separate the balancing element body from the holding part of the mounting tool, for example in the form of holding hooks.

In one embodiment variant, the adjustably mounted part is mounted at the holding part of the mounting tool in a rotatable and displaceable manner. The part that is thus adjustably mounted can be connected in a torque-proof manner to the fixation element for fixating the balancing element, while the balancing element body remains retained at the holding part. For example, in a further development based thereon, the fixation element is mounted in a rotatable manner at the balancing element body and provided with an external thread. Via the external thread, the fixation element can be screwed in at a threaded section of the balancing element body provided with the internal thread to fixate the balancing element. As has already been explained above, in one embodiment variant, the fixation element can be brought into abutment with a first (external) side of the attachment section, and a second radially inner leg section of the wrap-around section can be clamped against the opposite second (internal) side of the attachment section in this manner. In an alternative embodiment variant, in which the fixation element is fixated at the second radially inner leg section in a form-fitting manner and the threaded section of the balancing element body is connected in one piece to the first radially outer leg section, the first and second leg sections are moved closer to each other by screwing in the fixation element (further). Likewise, in one embodiment variant, the fixation element can be brought into abutment with a second (internal) side of the attachment section, and a first radially outer leg section of the balancing element body can be clamped against the opposite first (external) side of the attachment section. Thus, by means of the two-part mounting tool, the balancing element body is brought into position in all cases, and the fixation element is subsequently screwed in to fixate the balancing element with the balancing element body and the fixation element in a desired balancing position in a clamping manner. By forming a rotatable fixation element that meshes with an internal thread of the balancing element body, a fixation of the balancing element can also be easily released by means of a correspondingly adjustable and in particular rotatably mounted part of the mounting tool, and the balancing element can be displaced.

In one variant, the adjustable fixation element is secured at the balancing element body against removal from the balancing element by means of a securing element. For instance, the adjustable fixation element is secured against removal from the balancing element in the radial direction with respect to the central axis. For instance, the fixation element thus cannot be easily twisted out of the balancing element body. By means of the securing element, which may for example be embodied as a securing ring, it can further be ensured also in the balancing element embodied as a multi-part that the adjustable fixation element is present at the balancing element body in a mounting position, before the balancing element is attached at the axially projecting attachment section of the rotor disc.

In principle, the fixation element can be embodied for example in the manner of a screw with a threaded section, a shaft and a (clamping) head, wherein the attachment section or one of the leg sections is acted on to fixate the balancing element by means of the (clamping) head.

The proposed mounting method can ultimately also be used in a proposed rotor arrangement, so that advantages and features that are explained above as well as in the following in connection with exemplary embodiments of such a rotor arrangement also apply to embodiment variants of a mounting method and vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

The attached Figures illustrate possible embodiment variants of the proposed solution by way of example.

FIG. 1 shows, in sections and in sectioned view, an embodiment variant of a rotor arrangement with a ring-shaped axially projecting attachment section at the rotor disc of a rotor.

FIG. 2 shows, in sectioned view and in a mounted state, the rotor arrangement of FIG. 1 with a balancing element in a high-pressure compressor of a gas turbine engine.

FIGS. 3A-3B show different views of the rotor arrangement of FIG. 2.

FIGS. 4A-4B show the balancing element of FIGS. 2 and 3A to 3B in sectioned view with an adjustably mounted fixation element in different positions.

FIGS. 5A-5C show the balancing element of FIGS. 4A and 4B in a mounted state at an axially projecting attachment section of the rotor of FIG. 1 in different phases during the fixation of the balancing element.

FIGS. 6A-6B show a further embodiment variant of a balancing element in different individual views.

FIGS. 7A-7B show a rotor arrangement with the balancing element of FIGS. 6A and 6B.

FIGS. 8A-8B show the rotor arrangement of FIGS. 7A and 7B with a balancing element in enlarged scale and in different views.

FIGS. 9A-9F show different views of the rotor arrangement with a mounting tool for attaching and fixating the balancing element of FIGS. 7A to 8B;

FIG. 10 shows, in enlarged scale, the two-part mounting tool with a view on a holding hook and an adjustably mounted rotating part of the mounting tool.

FIGS. 11A-11B show different perspective views of a further embodiment variant of a rotor arrangement with an alternatively embodied balancing element for the attachment at a rotor, for example according to FIG. 1.

FIG. 12 shows, in sections and in sectioned view, the rotor arrangement of FIGS. 11A and 11B in the mounted state in a high-pressure compressor of a gas turbine engine.

FIGS. 13A-13B show a further development of the embodiment variant of FIGS. 11A to 12, also rendering a part of the attachment section without (FIG. 13A) and with a balancing element (FIG. 13B), in a sectioned view.

FIGS. 14A-14E show a further embodiment variant of a rotor arrangement with a balancing element in which the balancing element engages around the attachment section by means of a radially outer leg section of a balancing element body and a section of a fixation element that is adjustably mounted at the balancing element body.

FIG. 15 shows, in a sectional view, a gas turbine engine in which an embodiment variant of the proposed rotor arrangement is used.

DETAILED DESCRIPTION

FIG. 15 shows, in a sectioned side view, a gas turbine engine T which in the present case is embodied as a turbofan engine. The individual components of the gas turbine engine T are successively arranged along a central axis or rotational axis M. Air is suctioned into the gas turbine engine T via a fan 12 of the gas turbine engine T at an inlet or intake 11. Behind the fan 12, the inflowing air is transported into two different channels, a primary flow channel A of a core engine K and a secondary flow channel or bypass channel B surrounding the core engine K. Inside the core engine K, a medium-pressure compressor 13 and a high-pressure compressor 14 are successively arranged along the rotational axis M to compress the inflowing air in the primary flow channel A. Subsequently, the air is transported into a combustion chamber 15 of the core engine K. Due to the combustion taking place in this combustion chamber 15 by means of the injected fuel, a turbine with a high-pressure turbine 16, a medium-pressure turbine 17 and a low-pressure turbine 18 is driven. Behind the low-pressure turbine 18, the exhaust gases created as a result of the combustion are discharged into the environment via an outlet 19.

At that, the turbine with the high-pressure turbine 16, medium-pressure turbine 17 and low-pressure turbine 18 in particular drives the fan 12 to create the desired thrust through the air that enters the bypass channel B.

Rotors with rotor blades that are mounted so as to be rotatable about the rotational axis M are provided in the medium-pressure and high-pressure compressors 13 and 14 as well as in the high-pressure, medium-pressure and low-pressure turbines 16, 17 and 18. To ensure an even rotation in these high-speed rotors, in particular in the area of the high-pressure compressor 14, the individual rotors of a rotor blade row are balanced. However, due to the installation space situation and the designs of the rotors as they have been customary so far, the attachment of corresponding balancing elements at predefined balancing positions at these rotors can be performed only with difficulties. The proposed solution is meant to remedy this problem.

FIG. 1 illustrates a first exemplary embodiment of a rotor arrangement with a rotor 2 in sections. This rotor 2 is for example provided for use in the high-pressure compressor 14 and is configured as a blisk. Here, a rotor disc 21 that mounts the rotor 2 so as to be rotatable about a rotational axis M is embodied integrally, i.e. in one part, with the rotor blades 20. The rotor disc 21 extends along a circumferential direction U about the centrally located middle axis M, which in the installed state of the rotor 2 coincides with the rotational axis M of the gas turbine engine T.

The rotor disc 21 forms a ring-shaped attachment section 22 at a downstream backside of the rotor disc 21, referring to the installed state of the rotor 2. This ring-shaped attachment section 22 is embodied to be axially projecting with respect to the central axis M, and extends along a circular path about the central axis M along the circumferential direction U. The attachment section 22 of the rotor 2 of FIG. 1 is further embodied to be slightly tilted radially outwards to facilitate accessibility to a fixation element 5 of a balancing element 3 attached at this attachment section 22 if the rotor 2 has been mounted according to the intended use. This is in particular illustrated in more detail in the sectional view of FIG. 2.

For balancing the rotor 2, a balancing element 3 is fixated at least at one balancing position along the circumference of the attachment section 22. At that, corresponding to the rendering of FIG. 2, the balancing element 3 has a balancing element body 4 with a wrap-around section 41 that engages around a part of the attachment section 22. The balancing element body 4 of the balancing element 3 is thus held in a form-fitting manner at the axially projecting attachment section 22, and can still be displaced at the same along the circumferential direction U into the desired balancing position along the attachment section 22.

The wrap-around section 41 of the balancing element body 4 forms a first radially outer leg section 41 a as well as a second, radially inner leg section 410 that is opposite in the radial direction. If the balancing element 3 has been attached at the attachment section 22 according to the intended use, a part of the attachment section 22 of the rotor disc 21 is received between the first and the second leg sections 41 a and 410. The radially inner leg section 410 thus faces a radially inwardly positioned internal side 221 of the attachment section 22, while the other, radially outer leg section 41 a faces a radially outer external side 220 of the attachment section 22.

In the present case, the balancing element 3 is embodied with at least two parts and in addition to the balancing element body 4 with the wrap-around section 41 has a fixation element in the form of a screw 5. This screw 5 is screwed in at a sleeve-shaped threaded section 40 of the balancing element body 4 in the area of the first radially outer leg section 41 a. For this purpose, the threaded section 40 forms a passage opening with an internal thread 400 in which the screw 5 meshes with an external thread. A clamping head 50 of the screw 5 protrudes at a radially inner end of the passage opening that is provided with the internal thread 400, and can be brought into abutment with the external side 220 of the attachment section 22.

At that, to adjust the screw 5 in the direction of the attachment section 22 or away from the same, the screw 5 is mounted at the threaded section 40 of the balancing element body 4 in a rotatable manner. If the screw 5 is screwed in (further) into the balancing element body 4, the clamping head 50 of the screw 5 is pressed against the external side 220 of the attachment section 22 if the balancing element body 4 is plugged onto the attachment section 22. The rotation of the screw 5 that abuts the attachment section 22 via the clamping head 50 ultimately leads to the balancing element body 4 being displaced radially outwards and thus the radially inner leg section 410 being displaced against the internal side 221 of the attachment section 22. Thus, by turning the screw 5, a distance between the clamping head 50 of the screw 5 and the radially inner leg section 410 can be reduced, and the balancing element 3 can be fixated at the axially projecting attachment section 22 in this way.

For tightening and loosening the screw 5, it has a radially externally positioned tool interface 51, for example with an internal hexagon. At this tool interface 51, the screw 5 can be connected to a mounting tool in order to adjust the screw 5 relative to the balancing element body 4 which can be fixated at the attachment section 22. In the mounted state of the balancing element 3, the tool interface 51 of the screw 5 is accessible from the outside via a radially outwardly positioned installation gap 100 that is formed between the rotor 2 and an engine component TK of the gas turbine engine T axially connecting thereto. The further engine component TK can for example be a further rotatable rotor of the high-pressure compressor 14.

In the present case, the balancing element 3 embodied as a multi-part and the axially projecting attachment section 22 of the rotor 2 are adjusted to installation space conditions in such a manner that the tool interface 51 of the screw 5 remains accessible from the outside via the installation gap 100 if the rotor 2 is already connected to further engine components TK according to the intended use. Thus, also in the assembled state of a rotor assembly group comprising the rotor 2 with the at least one balancing element 3, a mounting tool can be applied to the screw 5 to tighten the screw 5 and thus fixate the balancing element 3 at the attachment section 22. Likewise, the screw 5 can also be turned in the rotor assembly group for detaching the fixation, and then the balancing element body 4 can be displaced into a different balancing position along the attachment section 22 in the circumferential direction U.

A curvature 410 a, which is convex in the direction of the internal side 221, is embodied at the radially inner leg section 410 of the wrap-around section 41. This convex curvature 410 a is engaged behind the axially projecting attachment section 22, and a physical guidance of the balancing element body 4 along the attachment section 22 is provided if the screw 5 is not yet fully tightened and does not yet abut the external side 220 of the attachment section 22 in a clamping manner via its clamping head 50.

FIGS. 3A and 3B again illustrate, in different perspective views, the form-fit wrap-around engagement of the balancing element 3 at the axially projecting ring-shaped attachment section 22 of the rotor disc 21. The wrap-around section 41 of the balancing element body 4 is C-shaped in side view, and has a radially outwardly extending sleeve-shaped threaded section 40 at the outer leg section 41 a. The screw 5 that is screwed into the threaded section 40 can be screwed in further into the threaded section 40 in the direction of the radially inner leg section 410, and thus fixate the balancing element 3 at the attachment section 22.

As illustrated based on the sectional views of FIGS. 4A and 4B, the screw 5 forms a contact surface 500 at its clamping head 50, which can be brought into a planar contact with the external side 220 of the axially projecting attachment section 22 for fixating the balancing element 3. For this purpose, the screw 5 can be adjusted through rotation about a screw axis along a rotational direction D1 in a displacement direction V1 towards the second, and in the mounted state radially inner, leg section 410. If, by contrast, the screw 5 is turned into an opposite rotational direction D2, the screw 5 is displaced into an opposite displacement direction V2 away from the second leg section 410, and thus a distance between the contact surface 500 of the clamping head 5 and the second leg section 410 is enlarged.

For assembling the balancing element 3, the screw 5 is initially screwed into the threaded section 40 so far that the clamping head 50 protrudes at an inner end of the threaded section 40. Then, a securing element in the form of a securing ring 52 is attached at the protruding end to axially secure the screw 5 at the balancing element body 4 and to avoid it from being twisted out of the threaded section 40. Thus, the securing ring 52 limits the adjustability of the screw 5 (in the area of the clamping head 50) in the direction of the displacement direction V2 relative to the balancing element body 4. Thus, the securing ring 52 is stopped at an end stop 401 inside the threaded section 40 and blocks any further displacement of the screw 5 along the displacement direction V2 beyond a predefined relative position between the clamping head 50 and the second leg section 410. A mounting position of the screw 5 at the balancing element body 4 is also predefined by the securing ring 52 to be able to easily attach a balancing element 3 at the attachment section 22 of the rotor 2, so that the wrap-around section 41 of the balancing element body 4 engages around a part of the attachment section 22.

As illustrated based on FIG. 5A in sectional view, after the balancing element 3 has been attached, the clamping head of the screw 5 abuts in a planar manner at the attachment section 22 at its external side 220 due to gravity. In contrast, the radially internally positioned second leg section 410 of the wrap-around section 41 is still arranged at least at a small distance from the internal side 221 of the attachment section 22. A slot s is present between the bottom side 221 and the convex curvature 410 a of the inner leg section 410. The balancing element body 4 is thus still displaceable at the attachment section 22 in the circumferential direction U, although the balancing element body 4 is already plugged onto the axially projecting attachment section 22, so that a part of the attachment section 22 is received inside mounting jaws 30 of the wrap-around section 41 that is defined between the two leg sections 41 a and 410 (cf. also FIG. 4B).

If now the screw 5 is screwed in further and thus the balancing element body 4 is displaced radially outwards via the internal thread 400 of its threaded section 40 that combs with the external thread of the screw 5, for one thing a distance between the contact surface 500 of the clamping head 50 of the screw 5 and the radially inner leg section 410 is reduced, and, for another, the radially inner leg section 410 is pressed against the internal side 221 of the attachment section 22. This phase during the fixation of the balancing element 3 is illustrated based on FIG. 5B.

If the screw 5 is tightened strongly enough, as illustrated in FIG. 5C, the balancing element 3 is held at the attachment section 22 around which its balancing element body 4 is engaged not only in a form-fitting manner, but is also fixated at it in a clamping manner. The balancing element 3 is thus fixated immovably in an occupied balancing position at the attachment section 22, and can be displaced only when the fixation is released by turning the screw 5 at the rotor 2.

FIGS. 6A to 8B show a further embodiment variant of a balancing element 3 with a balancing element body 4 that is geometrically modified as compared to the embodiment variant of FIGS. 2 to 5C. In side view, the balancing element body 4 of the embodiment variant of FIGS. 6A to 8B has a trapezoidal contour, wherein in the mounted state of the balancing element body 4 the longer side of the trapezoidal contour abuts an axially projecting attachment section 22 of a rotor radially inside. In the present case, two second leg sections 410 and 411 are embodied at this radially inner side, being separated from each other by a recess 412. Here again, each of the leg sections 410 and 411 has a convex curvature 410 a or 411 a for abutment at the attachment section 22 in the fixated state of the balancing element 3. Via the two second leg sections 410 and 411, the balancing element body 4 can be brought into contact with an attachment section 22 at two locations that are spatially separated from each other along the circumferential direction U. Here, material is saved thanks to the recess 412. At the sides, the recess 412 is bordered by two facing cross webs 412 a and 412 b. These cross webs 412 a, 412 b extend between the respective second leg section 410 or 411 and first leg section 41 a. In the mounted state of the balancing element 3, these cross webs 412 a, 412 b thus extend substantially radially with respect to the central axis M.

The trapezoidal contour of the balancing element body 4 and in particular of the wrap-around section 41 reduces stresses occurring inside the balancing element body 4 if the screw 5 is tightened and the balancing element 3 is fixated at the rotor disc 21 in this manner. Against this background, there are also lateral, obliquely extending force introduction sections 413 and 414 embodied at the wrap-around section 41, which respectively connect one of the second leg sections 410 or 411 to the first leg sections 41 a at which the threaded section 40 with the passage opening is embodied with an internal thread 400 for the screw 5.

Further, a middle part 145 is embodied between these lateral force introduction sections 413 and 414 of the wrap-around section 41, which is embodied so as to be deepened or set back as compared to the adjoining force introduction sections 413 and 414. Due to the associated local reduction of a wall thickness of the wrap-around section 41 in a middle area between the two force introduction sections 413 and 414, the weight of the balancing element body 4 is even more reduced, and, despite the two second leg sections 410 and 411, differs only minimally from the weight of a balancing element body 4 with only one single second leg section 410. Further, an interface for a holding part 64 of a mounting tool 6, by means of which the balancing element body 4 of the balancing element 3 can be attached at the rotor 2, is provided by the backset middle part 415. This is illustrated in more detail in the following based on the FIGS. 9A to 9F that will be explained in the following.

For additional weight reduction at the rotor 2, one embodiment variant of the rotor arrangement corresponding to FIGS. 7A to 8B further provides that multiple individual attachment sections 22 arranged at a distance to one another are embodied at the rotor disc 21 along the circumferential direction U. What is accordingly provided is not an individual ring-shaped attachment section 22, but rather a plurality of attachment sections 22 that are distributed across the circumference of the rotor disc 21. Thus, these attachment sections 22 define possible balancing positions at which a balancing element 3 can be attached according to the intended use. A recess 23 is provided between respectively two neighboring attachment sections 22. This recess 23 respectively represents an intermediate area with an axial extension that is reduced as compared to the attachment section 22.

Three attachment areas 22 a, 22 b and 22 c axially projecting in a tongue-like or web-like manner are embodied at each attachment section 22. Here, a middle attachment area 22 c is present between two outer attachment areas 22 a and 22 b. A gap 223 ac or 223 bc extending in the circumferential direction is respectively provided between an outer attachment area 22 a or 22 b and the middle attachment areas 22 c. One of the cross webs 412 a, 412 b of the balancing element body 4 is received at least partially inside each of these gaps 223 ac, 223 bc when the balancing element 3 is attached according to the intended use.

Here, the respectively outer attachment areas 22 a and 22 b of an attachment section 22 are provided for connection with respectively one of the second, and in the mounted state radially inner, leg sections 410 and 411 of the balancing element body 4. The middle attachment area 22 c located in between serves for contact with the screw 5 provided for fixating. Consequently, if a balancing element 3 is fixated according to the intended use at an attachment section 22 of FIGS. 7A to 8B, respectively one leg section 410 or 411 presses along a radially outwards pointing direction against an internal side 221 of an outer attachment area 22 a or 22 c. Via the contact surface 500 at the clamping head 50, the screw 5 in turn presses against the middle attachment area 22 c at an external side 220 along a radially inward pointing direction. Thus, through the division of an attachment section 22 into different attachment areas 22 a to 22 c, the position of a balancing element 3 to be fixated thereat is largely predefined.

If, in one embodiment variant of a rotor arrangement according to FIGS. 7A to 8B, a fixation of a balancing element 3 by means of a screw 5 is released, the respective balancing element 3 can be shifted to another attachment section 22 along the circumferential direction U. At that, respectively at least a small axial projection may be present also in the area of the recesses 23 of the rotor disc 21, around which the wrap-around section 41 of the balancing element body 4 can engage and along which the balancing element 3 is thus held in a physically guided manner.

As shown in the view of FIG. 8A with a view onto the radially internally located side of the attachment section 22, in the newly taken balancing position, the balancing element body 4 with its wrap-around section 41 should again abut at the outer attachment areas 22 a and 22 b with its two second radially inner leg sections 410 and 411, so that the middle attachment area 22 c, against which the clamping head 50 of the screw 5 presses on the radially outer side, is located inside the recess 412 between the two second leg sections 22 a and 22 b.

To render mounting of a balancing element 3 easier, an especially embodied mounting tool can be used, by means of which, on the one hand, the balancing element body 4 is brought into position and, on the other hand, the screw 5 can be tightened for fixating the balancing element 3. FIGS. 9A to 9F and 10 illustrate an exemplary embodiment of such a mounting tool 6.

The mounting tool 6 has a rod-shaped holding part 64 with a sleeve portion 640 that a user can manipulate in order to position a balancing element 3 and handle the mounting tool 3. Further, a holding hook 641, at which the balancing element body 4 can be retained in a form-fitting manner, is embodied at an end of the holding part 64. For this purpose, the holding hook 641 engages radially around the balancing element body 4 in the area of the backset middle part 415. For the wrap-around engagement, a web 6410 embodied at the holding hook 641 extends obliquely to the middle part 415 at an internal side of the middle part 415 in the direction of the recess 412 of the balancing element body 4.

In the present case, the mounting tool 6 is embodied at least in two parts, and in addition to the holding part 64 has a rotating part 65. This rotating part 65 is embodied in a rod-shaped manner and is mounted inside the sleeve portion 640 of the holding part 64 so as to be rotatable and displaceable along a longitudinal extension direction of the sleeve portion 640. At least in the area of an end that can protrude from the sleeve portion 640 at an exit opening 6400 of the sleeve portion 640 in the area of the holding hook 641, the cross-sectional shape of the rotating part 65 corresponds to the inner contour of the tool interface 51 of the screw 5 at the balancing element 3. In the present case, the rotating part 65 is for example embodied with a hexagonal profile to mesh with the tool interface 51 of the screw 5 in a form-fitting manner.

If the balancing element 3 has been attached at the rotor disc 21 by means of the mounting tool 6, so that the balancing element body 4 of the balancing element body 4 held at the holding hook 641 engages around an attachment section 22, a section of the rotating part 65 is accessible, for example at a radially outer end of the sleeve portion 640, so that a user can rotate the rotating part 65 relative to the holding part 64. Through the rotation of the rotating part 54, the screw 5 that is in mesh with the same is then turned, and thus the balancing element 3 is fixated at the attachment section 22, or such a fixation is released. Due to the balancing element body 4 being held at the holding hook 641 of the mounting tool 6 in a form-fitting manner, the mounting tool 6 can also be used for displacing the balancing element 3 into another balancing position at the rotor disc 21 if the fixation is released.

To remove the mounting tool 6 from the balancing element 3 that is fixated according to the intended use, the rod-shaped rotating part 65 is pulled radially outwards. Here, the end of the rotating part 65 that is to be brought into mesh with the screw 5 is pulled into an exit opening 6400 of the sleeve portion 640 embodied at the radially inner end (cf. FIG. 10), so that the rotating part 65 and the screw 5 of the balancing element 3 are no longer in mesh. Subsequently, the holding part 64 is tilted so far that the web 6410 of the holding hook 641 no longer engages around the middle part 415 of the wrap-around section 41. Then, the mounting tool 6 can be removed from the balancing element 3 through the installation gap 100. Also in the mounted state of the rotor 2, the mounting tool 6 can again be moved towards the balancing element 3 through the installation gap 100, release the fixation, and displace the balancing element 3 into another balancing position.

In the embodiment variant of a rotor arrangement illustrated by FIGS. 11A-11B and 12, an alternatively embodied multi-part balancing element 3 is proposed. In this variant, it is not a clamping head 50 and at least one leg section 410 or 411 that abut the attachment section 22 for fixating the balancing element 3 at an axially projecting attachment section 22 of the rotor disc 21. Rather, here two facing leg sections 41 a and 410 are provided for clamping abutment at the attachment section 22. Here, a fixation element in the form of a screw 5 for the clamping fixation of a balancing element body 4 forming the two leg sections 41 a and 410 at a wrap-around section 41 is provided for reducing the distance between the first and the second leg sections 41 a and 410.

The screw 5 extends through a passage opening at the second leg section 410 that is located radially inside in the mounted state, and engages behind this second leg section 410 with a clamping head 50. Thus, the contact surface 500 formed at the clamping head 50 of the screw 5 abuts a radially inner side of the second leg section 410. If the screw 5 is tuned via its tool interface 51, so that the screw 5 is displaced into a radially outwards pointing direction, the clamping head 50 presses against the second radially inner leg section 410 and presses it in the direction of the other, first radially outer leg section 41 a. The part of the attachment section 22 around which the leg sections 41 a, 410 of the wrap-around section 41 of the balancing element body 4 are engaged is thus clamped in between the two leg sections 41 a and 410.

In order to optionally allow for an elastic displacement of the two leg sections 41 a and 410 towards each other and away from each other through the rotation of the screw 5, they are connected to each other by means of a presently convexly curved connection portion 416 that allows for a displacement of the one leg section 410 relative to the other leg section 41 a.

In order to avoid having to provide bores for the screw 5 of the balancing element 3 at the (blisk) rotor 2, a shaft 53 of the screw 5 extending between the leg sections 41 a and 410 extends in an axially offset manner with respect to a front face of the attachment section 22. Thus, the shaft 53 of the screw 5 extends past the attachment section 22 and not through the same.

In a possible further development of the embodiment variant of the FIGS. 11A-11B and 12, the balancing element body 4 can also be embodied with two radially inner leg sections 410 and 411 analogously to the embodiment variant of FIGS. 6A-6B. In that case, the leg sections could consequently be displaced in the direction of a (single) radially outer leg section 41 a by rotating the screw 5, and could thus be pressed against the attachment section 22 (in particular against a divided attachment section corresponding to FIGS. 7A to 8B) to fixate the balancing element 3 in a desired balancing position at the rotor disc 21 of the rotor 1 in a releasable manner.

In the embodiment variant of a rotor arrangement that is illustrated in the different views of FIGS. 13A and 13B, what is again provided, analogously to the embodiment variant of FIGS. 11A-11B and 12, is a balancing element 3 with facing leg sections 41 a and 410 that can be moved closer to each other by means of a screw 5 as the fixation element in order to fixate the balancing element 3 at the attachment section 22. Here too, the clamping head 50 of the screw 5 engages behind the radially inner leg section 410 and thus presses the leg section 410 to the attachment section 22 when the screw 5 is turned. However, in contrast to the variant of FIGS. 11A to 11B and 12, in this case the balancing element body 4 is provided with a connection portion 416 that is only barely curved or not curved at all, and that connects the two leg sections 41 a and 410 to each other. In this way, the balancing element body 4 is more slim and requires less installation space. A reduced wall thickness is provided at the connection portion 416 for the displaceability of the two leg sections 41 a and 410 with respect to each other, and thus as certain degree of flexibility is introduced in a targeted manner.

In the embodiment variant of a rotor arrangement that is shown in FIGS. 14A to 14E in different views, a balancing element 3 mounted according to the intended use engages around an axially projecting attachment section 22, with a section of the balancing element body 4 abutting the radially outwardly positioned external side 220 of the attachment section 22, and a section of the fixation element abutting the radially inwardly positioned internal side 221 of the attachment section 22, here in the form of the clamping head 50 of the screw 5. Hence, here the attachment section 22 is enclosed between the balancing element body 4 and a section of the fixation element 5 and is clamped between then if the balancing element 3 is fixated according to the intended use. Accordingly, in this case the mounting jaws 30 of the balancing element 3, inside of which the enclosed part of the attachment section 22 is received, are formed by a section of the balancing element body 4 and the clamping head 50 of the screw 5.

As shown in the combined view of FIGS. 14A to 14E, the clamping head 50 of the screw 5 engages behind the attachment section 22 and, in the fixated state of the balancing element 3 according to the intended use, directly abuts the internal side 221 of the attachment section 22 via its contact surface 500. At the opposite external side 220, the balancing element body 4 abuts the attachment section 22 via an abutment surface 4100. In the present case, the clamping head 50 is embodied in a disc-shaped manner and thus has a contact surface 500 that is provided for abutment at the attachment section 22, extending in a tilted manner with respect to the extension plane of the shaft 53 of the screw 5. The abutment surface 4100 of the balancing element body 4 is likewise beveled. In the case of the contact surface 500 of the clamping head 50 as well as in the case of the abutment surface 4100 of the balancing element body 4, the respective bevel corresponds to a correspondingly tilted course of the internal side 221 or the external side 220 of the attachment section 22, so that, when the screw 5 is tightened, a spline connection is provided on both sides of the attachment section 22 and the balancing element 3 is aligned to the attachment section 22 in a self-acting manner. This is illustrated in particular based on the sectioned views of FIGS. 14A and 14B.

At that, FIG. 14A shows the balancing element 3 in a position in which the screw 5 is not yet tightened. Consequently, a slot remains between the contact surface 4100 of the balancing element body 4 and the external side 220 of the attachment section 22, as well as between the contact surface 500 of the clamping head 50 and the internal side 221 of the attachment section 22. The balancing element 3 is thus still held at the attachment section 22 in a displaceable manner. FIG. 14B illustrates the balancing element 3 that is then fixated at the attachment section 22 in a clamping manner by tightening the screw 5.

The abutment surface 4100 of the balancing element body 4 is formed at an (outer) leg section 41 a that is located opposite the clamping head 50. Projecting from this leg section 41 a radially inward are two cross webs 412 a, 412 b that are separated from each other by a recess 412. Thus, when the balancing element 3 is mounted at the rotor disc 21 according to the intended use, these cross webs 412 a and 412 b project radially inward from the leg section 41 a. Each of these cross webs 412 a and 412 b extends in the direction of the radially inwardly positioned internal side 221 of the attachment section 22 if the balancing element 3 has been attached at the attachment section 22 according to the intended use, but without engaging around the attachment section 22.

The pair of cross webs 412 a and 412 b lock the balancing element 3 against any twisting when the latter has been attached at the attachment section 22. Further, the two cross webs 412 a and 412 b ensure the physical guidance of the balancing element body 4 at the attachment section 22 along the circumferential direction U, so that here too the balancing element body 4 can be displaced along the ring-shaped protruding attachment section 22 into the desired balancing position until the screw 5 is tightened.

In the present case, the cross webs 412 a and 412 b extend on both sides of the shaft 53 of the screw 5. Thus, the end of the shaft 53 that transitions into the clamping head 50 extends inside the recess 412 of the balancing element body 4 that is bordered by the facing cross webs 412 a and 412 b.

In the rotor arrangement of FIGS. 14A to 14E, in the assembled state of the engine T according to the intended use, the clamping head 50 is further received inside an annular gap 7 that is formed, on the one hand, by the axially projecting attachment section 22 of the rotor 2 and, on the other hand, by an axial projection 8 of the further engine component TK. If the rotor 2 and the engine component TK are mounted according to the intended use, the projection 8 of the engine component TK, which preferably protrudes in the direction of the rotor disc 21 in a ring-shaped manner, extends over the clamping head 50. Thus, on the one side, the clamping head 50 faces towards the internal side 221 of the attachment section 22 in the radially outwards pointing direction, and, on the other side (at an axial distance to the internal side 221 of the attachment section 22), faces towards a bottom side of the projection 8.

During mounting of the engine T or of a rotor assembly group comprising the rotor 2 and the further engine component TK, the balancing element 3 is initially fixated at the attachment section 22 of the rotor disc 21, so that the balancing element body 4 and the clamping head 50 of the screw 5 engage around the attachment section 22, without finally fixating the balancing element 3 at the attachment section 22. The balancing element 3 is thus held in a captive manner at the attachment section 22, but is still displaceable at the attachment section 22 along the circumference. Subsequently, the rotor assembly group, in which the rotor 2 forms one stage and the further engine components TK form a further stage of the high-pressure compressor 14, is assembled. In this manner, the annular gap 7 is formed, inside of which the clamping head 50 is subsequently completely received. The balancing element 3 can still be displaced into a desired balancing position in the circumferential direction U, and can subsequently be fixated at the attachment section 22 of the rotor 2 in a clamping manner by tightening the screw 5. As can be seen in FIGS. 14A to 14E, for this purpose the tool interface 51 of the screw 5 still remains accessible from radially outside, even after rotor 2 and the engine component TK have been assembled.

PARTS LIST

-   100 installation gap -   11 inlet/intake -   12 fan -   13 medium-pressure compressor -   14 high-pressure compressor -   15 combustion chamber -   16 high-pressure turbine -   17 medium-pressure turbine -   18 low-pressure turbine -   19 outlet -   2 rotor -   20 rotor blade -   21 rotor disc -   22 attachment section -   220 external side -   221 internal side -   223 ac, 223 bc gap -   22 a, 22 b outer attachment area -   22 c middle attachment area -   23 recess (intermediate area with reduced axial extension) -   3 balancing element -   30 mounting jaws -   4 balancing element body -   40 threaded section -   400 internal thread -   401 ledge -   401 wrap-around section -   41 a outer leg section -   410, 411 inner leg section -   410 a, 411 a curvature -   4100 abutment surface -   412 recess -   412 a, 412 b cross web -   413, 414 force introduction section -   415 middle part -   416 connection portion -   5 screw (fixation element) -   50 clamping head -   500 contact surface -   51 tool interface -   52 securing ring (securing element) -   53 shaft -   6 mounting tool -   64 holding part -   640 sleeve portion -   6400 exit opening -   641 holding hook -   6410 web -   65 rotating part -   7 annular gap -   8 projection -   A primary flow channel -   B secondary channel/bypass channel -   D1, D2 rotational direction -   K core engine -   M central/rotational axis -   s slot -   gas turbine engine -   TK engine component -   U circumferential direction -   V1, V2 displacement direction 

1. A rotor arrangement, with a rotor for an engine, having a rotor disc extending along a circumferential direction about a central axis, and at least one balancing element that is attached at the rotor disc for balancing the rotor, wherein at least one attachment section projecting axially with respect to the central axis is embodied at the rotor disc, and the at least one balancing element engages around the axially projecting attachment section.
 2. The rotor arrangement according to claim 1, wherein the at least one balancing element has a balancing element body with a wrap-around section by means of which the balancing element engages around the axially projecting attachment section.
 3. The rotor arrangement according to claim 2, wherein the wrap-around section has at least one—with respect to the central axis—radially outer first leg section and at least one radially inner second leg section, and wherein at least a part of the axially projecting attachment section is received between the first and the second leg sections.
 4. The rotor arrangement according to claim 3, wherein at least one of the first and second leg sections has a curvature that is convex in the direction of the attachment section.
 5. The rotor arrangement according to claim 1, wherein the at least one balancing element comprises a balancing element body and a fixation element that is adjustable relative to the balancing element body.
 6. The rotor arrangement according to claim 5, wherein the balancing element engages around the axially projecting attachment section by means of at least one section of the balancing element body and at least one section of the fixation element.
 7. The rotor arrangement according to claim 3, wherein the at least one balancing element comprises a balancing element body and a fixation element that is adjustable relative to the balancing element body, and wherein, for fixating the balancing element at the attachment section, the fixation element is configured and adjustably mounted relative to the balancing element body in such a manner that a radial distance of the first and second leg sections can be modified by adjusting the fixation element.
 8. The rotor arrangement according to claim 7, wherein the fixation element extends with one section between the first and the second leg sections radially with respect to the central axis.
 9. The rotor arrangement according to claim 8, wherein the section of the fixation element extending between the first and the second leg sections extends not through the attachment section, but instead past it.
 10. The rotor arrangement according to claim 5, wherein, for fixating the balancing element at the attachment section, the fixation element is configured and adjustably mounted relative to the balancing element body in such a manner that the fixation element can be brought into contact with the attachment section.
 11. The rotor arrangement according to claim 5, wherein the fixation element forms a contact surface via which the fixation element acts on one of the first and second leg sections or the axially projecting attachment section for fixating the balancing element at the attachment section.
 12. The rotor arrangement according to claim 1, wherein the wrap-around section has a trapezoidal contour, as viewed in a side view along the central axis.
 13. The rotor arrangement according to claim 1, wherein the at least one balancing element has a balancing element body with a wrap-around section by means of which the balancing element engages around the axially projecting attachment section, and wherein the wrap-around section has at least one—with respect to the central axis—radially outer first leg section and at least one radially inner second leg section, and wherein at least a part of the axially projecting attachment section is received between the first and the second leg sections, and the wrap-around section has two second radially inner [leg sections] that are located opposite a first radially outer leg section.
 14. A method for mounting a balancing element at a rotor that is rotatable about a central axis and has a rotor disc with at least one—with respect to the central axis—axially projecting attachment section, wherein the method comprises at least the following steps: providing a balancing element with mounting jaws, and attaching the balancing element at the at least one attachment section, so that the balancing element engages around the attachment section and at least a part of the attachment section is received inside the mounting jaws.
 15. The method according to claim 14, wherein the balancing element comprises (a) a balancing element body with a wrap-around section, wherein the wrap-around section has at least two facing leg sections that define the mounting jaws, or (b) a balancing element body and a fixation element adjustably mounted thereat, wherein the mounting jaws engaging around the attachment section is defined by a section of the balancing element body and a section of the fixation element.
 16. The method according to claim 14, wherein the balancing element attached at the attachment section is displaced into a balancing position along a circumferential direction about the central axis, and is subsequently fixated.
 17. The method according to claim 14, wherein an adjustably mounted fixation element of the balancing element is adjusted for fixating the balancing element in a balancing position at the attachment section.
 18. The method according to claim 14, wherein a mounting tool at which a balancing element body of the balancing element is held in a form-fitting manner and by means of which the balancing element body is further displaced into the balancing position is used for attaching the balancing element body at the attachment section.
 19. The method according to claim 17, wherein a mounting tool at which a balancing element body of the balancing element is held in a form-fitting manner and by means of which the balancing element body is further displaced into the balancing position, is used for attaching the balancing element body at the attachment section, and wherein the mounting tool is embodied in at least two parts with a holding part that holds the balancing element body in a form-fitting manner and a part for the displacement of the fixation element adjustably mounted at the holding part.
 20. The method according to claim 19, wherein the adjustably mounted part is mounted so as to be rotatable and displaceable at the holding part, and is connected in a torque-proof manner to the fixation element for the fixation of the balancing element, while the balancing element body remains retained at the holding part. 